The present invention relates to fiber-optic communications networks, and more particularly, to Raman amplifier systems for fiber-optic communications links.
Fiber-optic networks are used to support voice and data communications. In optical networks that use wavelength division multiplexing, multiple wavelengths of light are used to support multiple communications channels on a single fiber.
Optical amplifiers are used in fiber-optic networks to amplify optical signals. For example, optical amplifiers may be used to amplify optical data signals that have been subject to attenuation over fiber-optic paths. A typical amplifier may include erbium-doped fiber coils that are pumped with diode lasers. Raman amplifiers have also been investigated. Discrete Raman amplifiers may use coils of dispersion-compensating fiber to provide Raman gain. Distributed Raman amplifiers provide gain in the transmission fiber spans that are used to carry optical data signals between network nodes.
It is an object of the present invention to provide optical amplifier systems that use Raman pumps to pump transmission fiber spans to create distributed Raman amplification.
It is also an object of the present invention to provide optical amplifier systems that use Raman pumps to perform optical measurements that provide information on system characteristics.